This invention relates generally to systems including combustion engines, and more particularly to systems including a dual fuel combustion engine and method of operation of such a system.
In combustion engine applications, a combustor that is capable of operating on a gas fuel, a liquid fuel, or a mixture of both gas fuel and liquid fuel may be desirable. For example, by replacing a fraction of the liquid fuel by a gaseous fuel, it may be possible to achieve a reduction in emissions that is proportional to the dissolved fraction of gas fuel in liquid fuel. Further, because of lower emissions, combustion may be carried out at higher temperatures leading to an increase in an overall efficiency of the combustion engine. Such fuel flexibility, however, often requires complex and costly fuel injection systems that may sacrifice operability or performance when operating on one type of fuel or the other. Moreover, adapting such fuel injection systems in current combustion engines may present substantial challenges in fuel injection, as well as in maintaining nitrogen oxides and other types of regulated emissions below mandated levels. Since liquid fuels are about fifty times denser than gas fuels, the injection ports and fuel delivery networks required to inject liquid fuel would need to be much smaller and more complex than those typically used to inject gas fuel in a similar manner. There, is thus a need for an improved dual fuel combustion engines configured to inject gas fuel along with a liquid fuel into the combustor during operation.